<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>demo1</title>
</head>
<body>
    <div id="app">{{content}}</div>
</body>
<script src="vue.js"></script>
<script>
    
    // setTimeout(function(){
    //     var dom = document.getElementById('app');
    //     dom.innerHTML = 'hello world';
    // }, 2000)
    var app = new Vue({
        el: '#app',
        data: {
            content: 'hello world!'
        }
    })
    setTimeout(() => {
        app.$data.content = 'bye world!'
    }, 2000);
</script>
</html>